Materials

Tritanium

On page 134 of the Technical Manual, the power cell of the Type 1 and 2 phasers are described. One part reads 'When one considers that total stored energy of even the Type 1 phaser, if released all at once, is enough to vaporize three cubic metres of tritanium, it is reassuring to know that a full storage cannot be discharged accidentally'. We are subsequently told on the same page that the Type 1 phaser can hold 7.2 x 106 MJ

From this we can begin to guess at some of the properties of Tritanium. The equation which describes the energy needed to increase the temperature of a material is :

Which is some 65.96 times lower than the energy required for Tritanium!

So, Tritanium must therefore have a much higher density, boiling point, heat of vaporization, heat of fusion, or specific heat than aluminium - or some combination of the five. Since we have never been given figures for these numbers, we can never know which it is. Assuming only one factor differed there are five possible answers :

Assuming that only the boiling point was different, Tritanium would have a boiling point of about 975,420 K.

Assuming the only the density was different, Tritanium would have a density of about 178,090 kg/m3. Over fifteen times the density of lead.

Assuming the only the specific heat was different, Tritanium would have a specific heat of about 358,650 J/kg/K.

Assuming the only the heat of fusion was different, Tritanium would have a heat of fusion of about 2.654 x 109 J/kg.

Assuming the only the heat of vaporization was different, Tritanium would have a heat of vaporization of about 2.664 x 109 J/kg.

Conclusion

Tritanium is one of the major materials used in Federation starship and shuttlecraft hulls; given that the Type 6 personnel shuttle, with a length of 6 metres, only has a mass of 3.38 metric tons then it seems unlikely that the density of Tritanium can be all that high - and you'd have to wonder why designers would try to do the 24th century equivalent of building a 747 out of granite!

Boiling point is a potential candidate to be responsible for the higher energy, but the episode 'The Arsenal of Freedom' indicates that the hull of the Enterprise-D can only withstand a few thousand degrees before sustaining serious damage. While I guess it's possible for a substance to melt at, say, 5,000 K and not boil until near 1,000,000 K, it doesn't seem very likely.

The remaining three are probably the best candidates - it seems fairly certain that Tritanium has a high specific heat, heat of fusion, or heat of vaporization. More likely, a combination of the three.

The above treats Tritanium as a single substance, but Michael Voelker has pointed out that the episode 'Rascals' confirms that Tritanium is an alloy of some sort. The episode also reveals that the 'molecular structure' of some Tritanium had broken down, indicating that either one or more of the elements exists in molecular form, or that there is a compound in there somewhere.